Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: Is the cefoxitin disk diffusion test accurate enough?
Mimica, M. J.
Berezin, Eitan Naaman [UNIFESP]
Carvalho, R. L. B.
Mimica, I. M.
Mimica, L. M. J.
Safadi, Marco Aurelio Palazzi [UNIFESP]
Caiaffa-Filho, H. H.
Is part ofBrazilian Journal Of Infectious Diseases
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We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92%, respectively, and 98% specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98%, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.
CitationBrazilian Journal Of Infectious Diseases. Salvador: Contexto, v. 11, n. 4, p. 415-417, 2007.
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